Means for locking brush bristles in retaining structures



C. VAN CLIEF, JR

MEANS FOR LOCKING BRUSH BRISTLES IN RETAINING STRUCTURES Feb. 4, 1958 4Sheets-Sheet 1 Filed Feb. 16, 1955 INVENTOR. Will/AM c: m/v cut/.4?

nrrbbv'y PIGZ 1958 w. c. VAN CLIEF, JR 2,821,729

MEANS FOR LOOKING BRUSH BRISTLES IN RETAINING STRUCTURES Filed Feb. 16,1955 4 Sheets-Sheet 2 FIG. 5 L- Feb. 4, 1958 w. c. VAN CLIEF, JR

' MEANS FOR LOCKING BRUSH BR IQTLES IN RETAINING STRUCTURES 4Sheets-Sheet 3 k File'd Feb. 16, 195 5 F'GJZ INVENTOR, W/ZUAM c v/w cm";JR

' Feb. 4, 1958 w, C VAN CHEF, JR 2,821,729

MEANS FOR LOCKING BRUSH BRISTLES IN RETAINING STRUCTURES Filed Feb. 16,1955 4 Sheets-Sheet 4 YWIZUAM C V/M/ CZ/EFJQ INVENTOR.

United StatesPatent O MEANS FOR LOCKING BRUSH BRISTLES IN RETAININGSTRUCTURES William C. Van Clief, Jr., Baltimore, Md., assignor toPittsburgh Plate Glass Company, Allegheny County, Pa., a corporation ofPennsylvania Application February 16, 1955, Serial No. 488,499

9 Claims. (Cl. 15-181) This invention relates to rotary brushescomprising one, or a series of annular basic sections which are strungupon a mandrel, or which comprise a continuous channel strip woundspirally upon a mandrel, and it has particular relation to a lockingelement for the bristle holding means of such brushes.

Brushes have heretofore been constructed from socalled basic sectionsone type of which, termed a lock ring construction, comprises doubleended bristles folded about a ring-like core disposed between a pair ofannular side plates of sheet metal which are appropriately pressedtogether to provide annular brush section. One or a plurality of suchbasic sections may be threaded upon a power driven mandrel to provide arotary brush of relatively inexpensive construction. A brush of thistype is illustrated in the patent to Mertes 1,829,665.

Brushes comprising a continuous channel strip of metal spirally wound tofit over a power driven mandrel and comprising a core or filamentdisposed in the loops of double ended bristles within the channel, areillustrated in Peterson Patent 2,303,386 or Nelson Patent 2,609,242.

When either type of the foregoing constructions is embodied in a brushwhich is driven at considerable speed, much centrifugal force is exertedupon the bristles or upon the bristle holding element. In an effort toobviate these centrifugal forces, it has been suggested in the Petersonand Nelson patents to provide a strip within the channel having teethwhich project transversely of the channel strip (longitudinally withrespect to the brush) and engage the outer portion of the filamentarycore so that the latter is, in eifect, locked in position. In theseconstructions, the filamentary core can be regarded as holding means forthe bristles. The scale walls of the channel, with the teeth constitutelocking means for the core.

In the Peterson Patent 2,609,559, annular rings having teeth struck outlongitudinally are employed to lock annular basic sections constitutingbristle holding means on a mandrel.

In these constructions in which teeth are struck normally with respectto the plane of a sheet metal member such as an annular disc or a sidewall of a spirally wound channel, it is to be observed that the teeth,at their roots, are bent with respect to the plane of sheet metal inwhich they have their roots. The sharp bending at these points in aplane tends greatly to Weaken the teeth so that the strength thereof maynot be sufiicient adequately to resist centrifugal forces upon thebrushes composed of the basic sections or the channel strips when thebrushes are driven at high speeds.

In accordance with the provisions of this invention, it has been foundthat the rigidity or the strength of the teeth of a locking structurefor holding a bristle holding element upon a mandrel, can be greatlyincreased by pressing depressions of approximately semicircular sectionin the metal of the toothed annular discs or in the side walls ofcontinuous channels constituting the locking structure or means. Thesedepressions should be ice opposed to the teeth and the planes thereofshould blend into or become tangential at the teeth roots, to the curveof the walls of the depression.

The strengthening action occasioned by the depressions, such as abovedescribed, would appear to be due, at least in part, to the fact thatthe depressions provide relatively gradual curvature, blending the rootsof the teeth gradually into the plane of the metal of the annular sidediscs or of the side walls, as the occasion may be. Also the curve mayadd increased rigidity against longitudinal creasing or bending at theroots of the teeth, where the greatest stress is exerted.

For a better understanding of the invention, reference may now be had tothe accompanying drawings in which:

Fig. 1 is an elevational view of a brush composed of basic sectionsconstructed in accordance with the provisions of this invention;

Fig. 2 is a fragmentary sectional view dis-closing one form of basicsection and the mounting therefor, as employed in the rotary brushstructure of Fig. 1;

Fig. 3 is a fragmentary side elevational view of a basi sectionconstructed as disclosed in Fig. 2; i

Fig. 4 is a sectional view taken substantially upon the line IV-IV ofFig. 3;

Fig. 5 is a sectional view of a modified form of brush embodying lockingdiscs having teeth constructed in accordance with the provisions of thepresent invention; said discs being disposed between annular basicsections;

Fig. 6 is a fragmentary end view of the construction shown in Fig. 5;

Fig. 7 is a broken view partially in elevation and partially in sectionillustrating one application of a further embodiment of the invention toa brush comprising a spirally wound channel strip;

Fig. 8 is a view partially in section and partially in elevationillustrating a still further modification of the invention as applied toa spirally wound channel strip;

Fig. 9 is a fragmentary sectional view illustrating a modification ofthe tooth structure as employed in the practice of the invention;

Fig. 10 is a fragmentary elevational view of locking means employed inthe embodiment of the invention disclosed in Fig. 9;

Fig. 11 is a fragmentary sectional view of a further modification of theconstruction as shown in Fig. 7;

Fig. 12 is a sectional view taken substantially upon the line XIIXII ofFig. 8;

Fig. 13 is a perspective view partially in phantom outline of one formof basic section; and

Fig. 14 is a view in fragment and partially in phantom of a locking ringwhich may be employed in the practice of the invention.

In the embodiment of the invention as disclosed in Fig. l of thedrawings, a brush B is assembled from socalled basic sections which maybe of various designs. One embodiment of such section is illustrated inFig. 2 of the drawings and will be more fully described in a subsequentportion of this specification.

In the embodiment of the invention as disclosed, the sections are strungin well known manner upon an appropriate shaft or mandrel structure,such as the mandrel M illustrated in the drawings. The mandrel hasbearing portions 19, and is provided with shoulder portions 20 which areappropriately screw threaded and upon which are disposed the clampingnuts 21 that engage clamping plates 22.

A basic brush section suitable for mounting upon the mandrel as shown inFig. l of the drawings is illustrated in Figs. 2 and 3. This involves aso-called lock ring structure resembling those illustrated in thepatents to Mertes (preceding) or Frost 1,683,456. Theconstructionembodies annular side plates or discs constituting lockingPatented Feb. 4,

3 rings 23 and 24, one or both of which are formed with angularly spacedteeth 26 struck out normally with respect to the plane of the face ofthe disc and being disposed in radial planes. These teeth may be formedby shearing the metal of the disc as indicated in Fig. 3 to formopenings 27 in the form of the tooth, except that the roots of the teethat 28 are transversely uncut. Subsequently, the tabs of metal are bentoutwardly to position to form teeth as indicated in Fig. 2 of thedrawings.

In this embodiment of the invention, it will be observed that the sheetmetal contiguous or integral with the roots of the teeth is indented ordepressed as indicated at 29 in a direction with respect to the plane ofthe disc opposite to the teeth. In the construction as shown in Fig. 4,the roots of the teeth are blended or merged tangentially into thesemicylindrical walls of the depressions 29, thus reducing theconcentration of the stress at the point of: union between the metal ofthe teeth and the metal of the plate from which they are struck andotherwise stiffenmg the teeth at their roots. If desired further tostrengthen the teeth, the roots of the latter may be filleted asindicated at 30 in Fig. 3 of the drawings.

Bristles 31 of wire, tampico, plastic or the like between the plates 23and 24 preferably are of the double ended type in which each filament isof approximately twice the length desired in the brush bristles and isreplicately doubled about a central core structure or ring 32 of metalor other material of relatively high strength constituting holding meansfor the bristles.

Preferably, the core is of such outside diameter that the perimeterthereof will engage or substantially engage with the inner edges of theteeth 26, whereby the forces tending to spread or break the core are inpart transferred to the teet The inner diameter of the side discs isless than that of the core 32, and the outer diameter is less than thatof the circle defined by the tips of the bristles.

Means to maintain the locking rings 23 and 24 in desired position withrespect to each other, may comprise an appropriate central grommet 33 ofa diameter (internal) corresponding to the outer diameter of the mandrelM upon which the sections are to be strung or ganged. The grommet islocked in position in the locking rings by flanges 34, radiallyoutwardly upset about its edges.

As many basic sections as may be desired may be strung upon a mandrel Mand when in appropriate position, are pressed or clamped together andare held against rotationalmovement upon the mandrel by suitablytightening the nuts 21 against the plates 22 or by other convenientmeans. The strengthening of the teeth at the roots thereof by theformation of the depressions 29 in the side plates or discs addssubstantially to the overall strength of the construction; therefore,brushes so constructed may be driven at relatively high speed withoutdanger of the bristles or the bristle holding core 32 being released,displaced or brokenby reason of centrifugal force. As will be apparentfrom Fig. 2 of the drawings, the depressions in the metal accompanyingthe teeth 26- further form bosses. on. the opposite side that act asspacing means between contiguous basic sections, thus allowing air toflow between the sections to effect more rapid cooling of the latter,thus preventing overheating, or at least reducmg the tendency of thesections to overheat when they are subjected to heavy loads. If desired,in those instances where both plates 23 and 24 of contiguous units areformed with depressions, the depressions of one section may be sodisposed that they do not register with those of the contiguous section.However, if greater spacing between the basic sections is desired, thedepressions of contiguous sections may be disposed in register withrespect to each other, thus doubling the spacing bieftween contiguousunits and so increasing the cooling e ects.

The principles as applied to the reinforcement of lockrotary brushagainst centrifugal force is not necessarily limited to the constructionof annular brush sections such as are illustrated in Fig. 2 of thedrawings; but may be extended for example, to the construction ofbrushes comprising channel strips such as are illustrated in PetersonPatent 2,303,386. It will be observed that in the latter, a metallictape having vertically disposed teeth near each edge thereof is employedas securing means for double ended brush bristles of fiber, wire or thelike. The bristles are distributed along the tape with the mid portionsthereof contiguous to the center line of the tape, a core member of wireor other material is laid down upon the top of the bristles at their midportions and the sides of the tape are then bent upwardly in parallelismwith respect to each other so that the teeth extending vertically to theplanes of the side walls lock over the core, thus securing the bristlesin place. The sides of the channel so formed are in parallelism withrespect to each other are planar and are interconnected by aninterinediate web. This type of construction comprises a continuouschannel strip which may be wound spirally about an appropriate mandrelin order to form a rotary brush.

In Figs. 8 and 12 of the drawings is illustrated a channel element 36similar to that shown in the Peterson patent and comprising side walls37 and an interconnecting bottom web 38. Teeth 39 formal on the sidewalls by bending out the tabs from slots 41 in the side walls have rootportions remaining unsevered. For purposes of increasing the rigidity orstrength of these teeth to resist distortion or tearing at their roots,depressions 42 of semicircular section are formed in intermediateportions of the side walls and the walls of the depressions merge intoor become tangential to the planes of the teeth as already described sothat there is no abrupt angle between the roots of the teeth and theplanes of the side walls of the channel.

Double ended bristles 43 of wire, tampico, nylon or other plastic aredisposed within the channel and are held from outward displacement bybristle holding means comprising a core 44 of wire or other filamentarymaterial lying approximately in the median plane of the channel andbeing locked from outward displacement by means of the teeth 33 on sidewalls 37. A channel strip so formed may be wound as a spiral indicatedat 56 in Fig. 8 upon a driven mandrel 57. Such channel strip may forexample be mounted between end plates as shown in Fig. 7. The addedlocking strip (to be described) as shown in Fig. 7 is optional. Owing tothe reinforcing action of the depressions 42, the constructions areparticularly strong and are excellently adapted to resist thecentrifugal and other forces exerted upon the bristles and securingfilamentary. core of brushes driven at considerable speed.

In Fig. 7 of the drawings is illustrated a second mode of reinforcing aspirally wound channel strip upon a driven mandrel structure. Inthis'constru'ction, the mandrel is indicated at 60 as comprisingshoulders 61 which are screw threaded and have nuts 62 disposedthereupon for purposes of clamping end plates 63 and 64. The spirallywound strip 66 forming the brush 67 is disposed between these plates. Asillustrated in the drawings, the opposed faces of the end plates areshaped to a spiral or helical surface 68 and the ends of the strip 66may be abutted against shoulders 69 of the plates. Means securing theends of the strip upon the mandrel may be conventional and areillustrated as comprising devices 71, such as screws, or rivets'piercing the plates 63 and 64 and extending into the channel elements66.

The channel strip 66 in Fig. 7, is indicated as being free of lockingteeth. However, it is obvious that such teeth are optional and it may beprovided with teeth having reinforcementdepressions as shown in thelatter Figures Sand 12, or it may be provided with conventional teethsuch as are Shawn in the aforementioned patent ing teeth for maintainingbristle holding elements in a to Peterson. Naturally, thelatter'con'str'uction doesnot ment due to centrifugal forces.

games have the full strength to resist centrifugal forces or otheroperational forces characterizing in the construction shown in Figs. 8and 12 of the present application. However, for many purposes thereinforcing action of the locking strip to be described is sufiicient.

.As means for locking the spirally wound channel strip, shown in Fig. 7firmly upon the mandrel 60, even during high'speed operation, a spiralstrip 73 designed to be inserted between the turns of the strip 66 maybe provided. This strip 73 may be similar to that described in myapplication Serial Number 482,560 filed January 18, 1955 and ismentioned herein as constituting one embodiment under the genericprinciples of the present application. The spiral strip, as shown inFig. 7, is provided with teeth 74 struck out normally and being designedto engage the upper edge of one side wall of the strip 66.

Depressions 76 are also formed in the strip 73 so that the walls thereofblend into and are tangential to the roots of the teeth 74, as in themanner shown in Fig. 4. In the construction as shown, the depressions 76extend down only to the outer perimeter of the edges of the side wallsand the metal is bent in a line parallel to the edges of the strip 73. Alower edge is therefore provided upon each depression which, as shown inFig. 7, hooks over the side wall of the channel 66 which is not engagedby the teeth 74. In this construction, both side walls of the channelare very positively locked upon the mandrel against outwarddisplacement.

In the construction as illustrated in Figs. 7, 8 and 12 of the drawings,the channel strips are indicated as being spirally wound to provideelongated rotary brush structures which may be cylindrical r tapered. Itwill be apparent that the continuously wound spirals may also beappropriately cut, as for example, at the point or line indicated at Xin Fig. 8, into single ring-like turns. The single turns of the spiralcan be pressed by the exertion of but very slight force into planarrings or annular sections which though broken at the point of cutting,can be secured by a suitable locking annulus, as hereinafter described,and thus have sufiicient strength for many purposes.- Obviously, theends of the annulus could also be secured together by soldering,brazing, welding or by means of an appropriate clamp.

In Fig. 13 of the drawings, is indicated a single basic section 80formed by cutting off a single turn of the spiral shown in Fig. 8 of thedrawings. This annulus comprising the channel member 81 and bristles 82is similar to those shown in Figs. 8 and 12 and embodies angularlyspaced teeth with the roots thereof merged into, or tangential with thewalls of suitable depressions struck out from the walls on the sidesopposite from the teeth.

In the embodiment of the invention illustrated in Fig. 5, a series ofannular brush sections 89 which may be of .the channel constructionshown in Fig. 13 or otherap- -.projec ting edge flanges 93 adapted'toengage the end members of the series of plates 90. Means axially to,actuate the discs 92 to effect a clamping action comprises nuts 94threaded upon the mandrel and engaging the faces of the plates 92 sothat turning of the nuts move the plates along the shaft.

,It will be observed that each of the annular plates or discs 90 isprovided near the outer perimeter with a series of teeth 96, the rootsof which are blended into the side walls of depressions 97 in order tostrengthen them. Teeth 96 are adapted to hook over one side wall of thesection 89 to lock the same against outward move The lower portion ofeach depression may terminate in a slit and the edge thus provided maybe hooked over the walls of an adjacent section, thus positively lockingboth sidewalls of each section against centrifugal action.

6 Means constituting seats maintaining the sections 89 in concentricrelationship with respect to the shaft or mandrel 91, comprisesdepressions or indentations 98 pressed in the discs and having theirupper edges cut free by slitting to provide seats as at 99 for the innerperimeters of the channels of the sections. The depressions may beformed upon a single side of a disc near the outer perimeter thereof, oras illustrated in the drawings, they may be formed upon opposite sidesin perimetrically spaced relationship so that each annulus 89 issupported upon both sides.

For purposes of increasing the security of seating of the discs 90 uponthe mandrel 91, the discs may be provided about their inner perimeterswith flanges 100 seating upon the mandrel.

Further applications of the principles of the invention are disclosed inFigs. 9, 10, and 11 of the drawings. In the construction, as disclosedin Figs. 9 and 10, the locking device comprises sheet metal member 101which may be an annulus or a spiral strip, as may be desired (thefragment as disclosed in Figs. 9 and 10 being of either form); thiselement has teeth 102 struck out from the metal leaving openings 103. Adepression 104 is pressed into the metal across the entire width of theelement and the walls thereof are blended into or become tangential withrespect to the plane of the teeth 102 when the latter are in erectposition.

The construction of Figs. 9 and 10, if of spiral form, may be employedas is the strip 73 as shown in Fig. 7, the axially inner portions of thedepressions 104 being dis posed as spacers between contiguous turns ofthe strip 66. The positioning of such strip between the turns of thestrip 66 is illustrated in Fig. 9. Naturally, the member 101 may also beformed as an annulus designed to be placed between annular sections suchas are illustrated in Figs. 2 and 13.

In the construction as disclosed in Fig. 11 of the drawings, bristleholding means 105, such as basic sections or spiral turns, are formedand comprise as the holding means for the double ended bristles achannel 106 which may be wound as a spiral or may be an annulus, as maybe desired. The side walls of the strip are inwardly inclined withrespect to each other to provide a dove-tail section. The locking deviceor means for this construction comprises a sheet metal element 107 whichmay be an annular ring or spiral tape dependent upon whether the deviceis to be used to secure annular base sections or a spirally wound stripupon a mandrel, such as the mandrel 108. The locking means 107 includesteeth 109 struck out from the metal and having depressions 111 at theroots thereof and the planes of which blend into, or become tangent withrespect to the walls of'the depressions. It is to be observed that inthese constructions, the depressions 111 are not slit at their loweredges, but are wedged between contiguous side walls of adjacent basicsections or in event that the brush is of a spirally wound strip,between the side walls of contiguous turns. It is evident that in thisconstruction, the teeth 109 locking over the upper edges of the sidewall of the brush element (strip or annular section) securely hold oneside wall while the lower portion of the depression projecting in theopposite direction secures the other side wall by wedging action.

An appropriate locking ring which may be used with a basic sectioncomprising a trapezoidal section is fragmentarily illustrated in Fig.14. It comprises an annular ring of sheet metal indicated at 112 andhaving teeth 113 struck out leaving openings 114. Depressions 116 ofapproximately semicircular section and ovoid outline, are pressed intothe metal at the roots of the teeth, but project from the sides of themetal opposite the teeth. The depressions may be wedged between twobasic sections having inverted trapezoidal section while the inner edgesof the teeth bear upon the edges of the side walls. The depressio si assh wn. n P e .4, te mina a subs an i l distan r m th out r per me o ennulus. h s ss st in Pr vent n s re hing of h annul un t n ion- Theteeth, shown in the several embodiments, penetrate between the bristlesand assist in preventing peripheral creeping of the bristles. They alsotend to s-tiifen the bristles by shortening the length of unsupportedmaterial.

In those constructions, as shown in Figs. 2, 8, and 12, where teeth areprovided upon side walls of sheet metal channel or upon annular sideplates and in either instance where the teeth engage or lock afilamentary core which hold the bristles in place, the core may beregarded as being the holding means for the bristles; the toothed sidewalls of the channel or the side plates of a basic section may beregarded as locking means for the holding means. In those instanceswhere a separate spiral strip having teeth engaging the edge of a spiralchannel, having teeth as in Fig, 7 or a separate annular ring as in Fig.5, having angularly spaced teeth engaging the edges of the annular sideplate of a section is provided, the channel or side plates may be termedholding means for the bristles; the separate strip or separate ring maybe termed locking means for said holding means.

It will be apparent to those skilled in the art that the embodiments ofthe invention as herein disclosed are by way of illustration rather thanlimitation. Numerous modifications may be made therein Without departurefrom the spirit of the invention or the scope of the appended claims.

I claim:

1. A rotary brush structure comprising an axially extending core ofcircular section having bristle material projecting radially therefrom,holding means extending around the core and holding the bristles inplace upon the core, locking means for said holding means also extendingaround the support, said locking means comprising a radially projectingsheet metal element contiguous to and paralleling the holding means andprojecting substantially radially from the core and having a series ofperipherally spaced teeth projecting longitudinally of the core, saidteeth engaging the outer circumference of said holding means, said sheetmetal element further having depressions corresponding to the teethformed therein with an edge of each depression forming the roots of thecorresponding tooth and projecting upon the side of the sheet metalopposite the teeth, the roots of the teeth being integral with andblended into the walls of the depressions.

2. A locking ring for securing annular basic sections of; a rotary brushupon a mandrel, comprising an annular plate having a series ofperipherally spaced teeth normal to the plane of said plate and beingadapted to engage the outer perimeter of a side wall of one of saidbasic sections, the plate further having depressions formed therein andprojecting upon the side of the plate opposite the teeth, the, roots ofthe teeth being integral with and blended into the walls of saiddepressions, there being a depression for each tooth.

3. A rotary brush structure comprising a channel strip spirally woundupon a mandrel, said channel strip comprising a channel backing elementhaving a bottom with side walls projecting radially therefrom, doubleended brush bristles secured between the side walls and being held inposition by a filamentary core disposed in the looped portions of thedouble ended bristles, the side walls of the channel further havingintegrally formed, peripherally spaced teeth struck inwardly parallel tothe axis of the brush and being disposed in radial planes and engagingthe, filamentary core, and further having depressions struck outwardlyat the roots of the teeth, the roots of the teeth, being integral with,blended into, and being an inward continuation of the walls. of thedepressions, there being a depression for each tooth.

4. A locking ring for securing annular brush sections po a drel. c mprsing, annu ar pla adap d to fit upon the mandrel between a pair of brushsections and having a series of integrally formed peripherally spacedteeth struck out normal to the annular plate and being disposed inradial planes and being adapted to engage a side wall of a brush sectionupon the mandrel and further having a series of depressions formedtherein at the roots of the teeth and projecting upon the side oppositethe teeth, there being a depression for each tooth and the roots of theteeth being blended into and being an integral continuation of the wallsof the depressions, the depressions being terminated a substantialdistance within the outer perimeter of said annular plate.

5. Means for locking brush sections upon a rotary brush mandrelcomprising an annular plate having a series of peripherally spaced teethstruck out normally with respect to the plane of the plate, said teethbeing disposed in radial planes and being adapted to engage the outerperimeter of a side wall of a brush section mounted upon the mandrelcontiguous to the plate, said plate further having depressions struckradially there across from the inner to the outer perimeter andprojecting upon the side opposite the teeth, the roots of said teethbeing integral with, blended into and constituting a continuation of theside walls of the depressions.

6. Means for locking brush sections upon a rotary brush mandrelcomprising an annular plate having a series of peripherally spaced teethstruck out normally with respect to the plane of the plate, said teethbeing disposed in radial planes and being adapted to engage the outerperimeter of a side wall of a brush section mounted upon the mandrelcontiguous to the plate, said plate further having a series ofdepressions corresponding in number to the teeth struck radially thereacross from the inner to the outer perimeter and projecting upon theside opposite to the teeth at the roots thereof, the roots of said teethbeing integral with, blended into and constituting a continuation of theside walls of the depressions, the depressions being adapted toconstitute spacer elements between contiguous sections permittingmovement of air between said sections.

7. A rotary brush comprising a pair of annular basic sections mountedupon a central mandrel, a flat annular locking ring disposed upon themandrel between the section, said ring having teeth struck out normallyto the plane of the ring from a surface thereof and being disposed inradial planes and being adapted to engage the outer edge of a side wallof one of said basic sections and further having depressions struck fromthe side opposite the teeth, the roots of the teeth being integral with,blended into and constituting a continuation of the Walls of thedepression, the convex sides of the depressions having portions engagingthe outer perimeter of a side wall of a basic section contiguousthereto.

8. Means for supporting and locking an annular brush section upon arotary mandrel comprising an annular plate-like element adapted to seatupon a mandrel and having a series of peripherally spaced teeth struckthere from and projecting normally with respect to the face of the plateand being disposed in radial planes, a series of depressions formed inthe plate-like element at the roots of the teeth, and opposite indirection to the teeth, the teeth being integral with, and blended into,and being a continuation of the walls of the depressions, there being adepression for each tooth, the teeth being adapted to engage the outerperimeter of a brush section upon the mandrel, said plate further havinga second series of perpherally spaced depressions formed therein andprojecting to engage the inner perimeter of the section whereby tomaintain said section in centered relationship with respect to themandrel.

9. A rotary brush section comprising double-ended bristles doubledabouta ring-likecore and projecting outwardly from the core and annularplates engaging the sides of the bristle mass thus. formed, ring meansjoining the plates together to form a channel containing the ringtheroots of the teeth and projecting from the plate on like core, theplates being of an outer diameter less than the side opposite the teeth.that of the section and greater than that of the core and ReferencesCited in the file of this patent of an inner diameter less than that ofthe core, one of said plates having a series of angularly spaced teethstruck 5 UNITED STATES PATENTS normally therefrom in radial planes andengaging the core 1,829,665 Mertes Oct. 27, 1931 and a series ofindentations being formed in the latter 2,409,309 Peterson Oct. 15, 1946plate at the bases of the teeth, one of the depressions ,9 7 R086 0 7,950 being; for each tooth and the walls of the depressions 2,609,559Peterson P 9, 1952 being blended with, a continuation of, and integralwith 10 2683147 Nielson P 7, 1954

